I-5 bridge collapse over Skagit River

A four-lane Interstate 5 bridge over the Skagit river north of Seattle collapsed Thursday evening May 23, 2013, dumping vehicles and people into the water.

A portion of the Interstate 5 bridge is submerged after it collapsed into the Skagit River dumping vehicles and people into the water in Mount Vernon, Wash., Thursday, May 23, 2013 according to the Washington State Patrol. (AP Photo/Skagit Valley Herald, Frank Varga)

Rescue workers look for victims after a portion of the Interstate 5 bridge collapsed into the Skagit River in Mount Vernon, Wash., Thursday, May 23, 2013. (AP Photo/Everett Daily Herald, Jon Bauer)

A truck is seen in the water after a portion of the Interstate 5 bridge collapsed into the Skagit River in Mount Vernon, Wash., Thursday, May 23, 2013. (AP Photo/Everett Daily Herald, Jennifer Buchanan)

View looking west at a portion of the Interstate-5 bridge submerged after collapsing into the Skagit river dumping vehicles and people into the water in Mount Vernon, Wash., Thursday, May 23, 2013 according to the Washington State Patrol. (AP Photo/Joe Nicholson)

A portion of the Interstate 5 bridge is submerged after it collapsed into the Skagit River dumping vehicles and people into the water in Mount Vernon, Wash., Thursday, May 23, 2013 according to the Washington State Patrol. (AP Photo/Skagit Valley Herald, Frank Varga)

A rescue boat and divers search near a portion of the Interstate-5 bridge that is submerged after it collapsed into the Skagit river dumping vehicles and people into the water in Mount Vernon, Wash., Thursday, May 23, 2013 according to the Washington State Patrol. (AP Photo/Joe Nicholson)

A portion of the Interstate-5 bridge is submerged after it collapsed into the Skagit river dumping vehicles and people into the water in Mount Vernon, Wash., Thursday, May 23, 2013 according to the Washington State Patrol. (AP Photo/Joe Nicholson)

In this photo provided by Francisco Rodriguez, a man is seen sitting atop a car that fell into the Skagit River after the collapse of the Interstate 5 bridge there minutes earlier Thursday, May 23, 2013, in Mount Vernon, Wash. (AP Photo/Francisco Rodriguez)

In this photo provided by Francisco Rodriguez, rescue workers form a human chain as they begin to remove a woman who reaches out from a smashed pickup truck that fell into the Skagit River after the collapse of the Interstate 5 bridgeThursday, May 23, 2013, in Mount Vernon, Wash. (AP Photo/Francisco Rodriguez)